U.S. patent number 4,383,213 [Application Number 06/288,256] was granted by the patent office on 1983-05-10 for triodyne.
Invention is credited to Joseph M. Tyrner.
United States Patent |
4,383,213 |
Tyrner |
May 10, 1983 |
**Please see images for:
( Certificate of Correction ) ** |
Triodyne
Abstract
A dynamoelectric machine having a multiple of three poles and a
corresponding multiple of three brushes is disclosed. Each of the
poles are wound poles, two of each group of three poles being
excited with a constant excitation during normal operation, the
third of each group of poles being a control pole, excited so as to
produce a flux that both varies in magnitude and reverses in
polarity. With an input voltage connected to first and second
brushes of each group of three, an output voltage may be derived
from first and third brushes in a magnitude determined by the
polarity and intensity of the field of the control pole. The
machine is also adapted to provide mechanical output power from its
rotating shaft, and also to accept input power from its rotating
shaft. The output voltage obtainable may be varied between zero and
the value of the input voltage, and also increased above the input
voltage, and decreased below zero, reversing polarity. Means are
also disclosed for providing regenerative braking of a motor driven
by the output voltage of the machine and returning power to a
battery power supply without increasing shaft speed of the machine,
by augmenting the flux of a pole to increase the input voltage
while maintaining the output voltage constant.
Inventors: |
Tyrner; Joseph M. (Morristown,
NJ) |
Family
ID: |
26915776 |
Appl.
No.: |
06/288,256 |
Filed: |
July 27, 1981 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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221422 |
Dec 30, 1980 |
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Current U.S.
Class: |
322/53; 310/102R;
318/158; 318/376; 322/63 |
Current CPC
Class: |
H02K
47/16 (20130101); H02K 23/20 (20130101) |
Current International
Class: |
H02K
47/00 (20060101); H02K 47/16 (20060101); H02K
23/20 (20060101); H02K 23/02 (20060101); H02P
009/10 (); H02P 009/14 (); H02P 007/16 (); H02P
003/14 () |
Field of
Search: |
;310/4R,12R
;322/53R,91,63-66 ;318/376,344,158 ;320/61 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Hickey; R. J.
Attorney, Agent or Firm: Hopgood, Calimafde, Kalil,
Blaustein & Judlowe
Parent Case Text
The instant application is a continuation-in-part of application
Ser. No. 221,422 filed Dec. 30, 1980, now abandoned.
Claims
I claim:
1. Electrical control equipment for controlling the power supplied
to a load, said equipment comprising in combination a field
structure and an armature concentrically related and mounted for
relative rotation one with respect to the other, said field
structure including one or more sets of poles with each set
consisting of a first, a second and a third pole, all of said poles
being equidistantly spaced circumferentially around said field
structure, a commutator connected to said armature and engaged by
sets of brushes, with each set consisting of a first, a second and
a third brush, corresponding respectively to said first, second and
third pole, there being a set of brushes for each set of poles,
said brushes being equidistantly spaced circumferentially with
respect to said commutator, said first and second brushes being
provided with means for establishing connection with respective
terminals of a source of electrical power, said first and third
brushes being provided with means for establishing connection to
respective terminals of said load for furnishing electrical power
thereto, there being at least one excitation winding on each of
said poles, means connected to said excitation windings on said
first and second poles for coupling said last mentioned windings to
a source of energization for establishing first and second poles of
fixed and opposite magnetic polarity, and said windings on said
third poles are provided with means for changing the field current
in said windings from excitation of one polarity to excitation of
the opposite polarity and through all excitation levels inbetween,
to change the voltage delivered to said load.
2. Electrical control equipment according to claim 1, characterized
in that said poles in each set of poles are spaced 120 electrical
degrees apart.
3. Electrical control equipment according to claim 1, characterized
in that said second poles are provided with additional windings,
and means are provided coupled to said additional windings for
supplying a current thereto in a direction to augment the magnetic
field established by said second poles as a function of the current
flowing through said third brushes.
4. Electrical control equipment according to claim 3, characterized
in that said third poles are provided with additional windings, and
means are provided coupled to said additional windings on said
third poles for supplying a current thereto in a direction to
diminish the magnetic field established by said third poles as a
function of the current flowing through said second brushes.
5. Electrical control equipment according to claim 1, characterized
in that said first poles are provided with additional windings,
means are provided coupled to said additional windings on said
first poles for supporting a current thereto in a direction to
diminish the magnetic field established by said first poles as a
function of the current flowing through said third brushes, said
third poles are provided with additional windings, and means are
provided coupled to said additional windings on said third poles
for supplying a current thereto in a direction to augment the
magnetic field established by said third poles as a function of the
current flowing through said first brushes.
6. Electrical control equipment according to claim 1, characterized
in that said first poles are provided with additional windings,
means are provided coupled to said additional windings for
supplying a current thereto in a direction to augment the magnetic
field established by said first poles as a function of the current
flowing through said second brushes, said second poles are provided
with additional windings, and means are provided coupled to said
additional windings on said second poles for supplying a current
thereto in a direction to diminish the magnetic field established
by said second poles as a function of the current flowing through
said first brushes.
7. Electrical control equipment according to claim 1, characterized
in that said equipment is provided with mechanical output means and
is constructed and arranged to accept input electrical power and to
convert said input power into mechanical output power furnished to
said mechanical output means, and into adjustable electrical power
furnished to said load.
8. Electrical control equipment according to claim 1, characterized
in that said equipment is provided with mechanical input means and
is constructed and arranged to convert mechanical input received
from said mechanical input means into controlled electrical power
supplied to said load with excess electrical power being fed back
to said source of electrical power.
9. Electrical control equipment according to claim 1, characterized
in that said second poles are provided with an additional winding,
and means are provided for electrically exciting said additional
windings on said second poles when said load feeds back electrical
power to said equipment to increase the voltage across said first
and second brushes to force power back into said source of
electrical power for regenerative braking of said load when said
load is an electromechanical device.
10. Electrical control equipment according to claim 9,
characterized in that said means for electrically exciting said
additional windings on said second poles includes for such
additional windings first unidirectional conducting means connected
to shunt said additional windings when said equipment delivers
power to said load, and second unidirectional conducting means
connected in series with said additional windings to permit current
to flow through said windings when said load delivers power to said
equipment.
11. Electrical control equipment according to claim 1,
characterized in that said excitation windings on said second poles
are wound with the same number of turns as said excitation windings
on said first poles but with conductors of lesser resistance than
the conductors of said windings of said first poles, a series
resistor is disposed in series with each of said excitation
windings of said second poles, and means are provided for shunting
each of said series resistors when said load feeds back electrical
power to said equipment to increase the voltage across said first
and second brushes to force power back into said source of
electrical power for regenerative braking of said load when said
load is an electromechanical device.
12. Electrical control equipment according to claim 11,
characterized in that said means for shunting said series resistors
comprises a polarized relay actuated by electrical current flowing
to and from said load, said relay being constructed and arranged to
close a switch for shunting a respective resistor when current
flows from said load to said equipment.
13. Electrical control equipment according to claim 12,
characterized in that said polarized relay includes a yoke having
two legs surrounding a conductor carrying said current to and from
said load, and a relay body, said relay body including a pair of
permanent magnets, each of said permanent magnets including pole
shoe means, said pole shoe means defining confronting spaced apart
field poles facing opposite surfaces of said two legs of said yoke,
said relay body including a switch connected to at least one of
said resistors and operable by said yoke, said yoke being
magnetized with a first polarity when current flows through said
conductor to said load and being drawn towards a first one of said
magnets, and said yoke being magnetized with a second polarity
opposite to said first polarity when current flows through said
conductor from said load and being drawn towards the other of said
magnets to actuate said switch.
Description
This application is related to the field of dynamoelectric
machines. In particular, this application is related to direct
current dynamoelectric machines usable as voltage controllers.
BACKGROUND OF THE INVENTION
This application relates to various improvements to an
unsymmetrical dynamoelectric machine having an integral multiple of
three poles and an integral multiple of three brushes, performing
the general function of a motor-generator set in a single integral
device, and having capability of accepting or providing power from
its rotating shaft. Such a device, known as a Triodyne, is
disclosed in U.S. Pat. No. 2,388,023, issued to me on Oct. 30,
1945, and in U.S. Pat. No. Re. 22,907, reissued Aug. 12, 1947,
herein incorporated by reference. U.S. Pat. No. Re. 22,907 sets
forth the basic theoretical considerations for the design and
construction of such a machine.
A device in accordance with the claims of said patents has been
constructed, and performed satisfactorily as a voltage controller
for electrical welding, with the rotating shaft supporting the load
of a ventilating fan. In this application, the device was
satisfactory, and provided the low voltage, high current supply
needed for welding from a high voltage, low current source.
However, in an attempt to use this device as a voltage controller
for an electric vehicle, it was found by further analysis and
testing that the use of a device according to my previous patents
had serious drawbacks. Placing the winding for the main or motor
field on a single pole required a large winding, to overcome the
reluctance of two air gaps. This large winding in turn requires a
large, long pole piece, and a large frame diameter for the device.
This would also result in a cooling problem, since the device would
approximately double in volume with a less than sixty percent
increase in surface area. It was also found that such a
dynamoelectric machine would increase in speed upon an attempt to
return power from the load, such as for regenerative braking, an
undesirable effect in some applications.
Also, with a control pole being fully excited to provide minimum
output voltage, and turned off to provide maximum output voltage,
the maximum output voltage was further limited by residual
magnetism in the control pole, since the resultant residual flux
caused something less than full desired output, of an unpredictable
and unstable value.
The instant invention overcomes these and other deficiencies of the
prior art.
SUMMARY OF THE INVENTION
The invention is a dynamoelectric machine having an integral
multiple, i.e., one or more sets, of three poles, and an armature
which rotates in a fixed frame carrying the poles. On the
commutator of the armature are an integral multiple of three
brushes, located equidistantly from each other.
In a three pole dynamoelectric machine according to the invention,
an electrical power supply such as a battery, is connected to first
and second brushes. First and third brushes deliver controlled
voltage to a load, such as a traction motor of an electric vehicle.
Current may flow into the load to drive it. This current direction
is referred to as forward current. If current is returned to the
subject machine, it shall be called reverse current.
Two of the three field coils are permanently fully excited shunt
fields, while the third is a control coil. Its excitation may be
varied from full excitation in one polarity to full excitation in
the other polarity. Full excitation, for purposes of this
application, is defined as excitation producing equal magnetic
strength on three poles of a three pole machine according to the
invention, one pole having a fixed north polarity, one pole having
a fixed south polarity, and one pole being continuously variable
from north to south polarity, by excitation which varies
continuously from full excitation with current flowing in its
winding in a first direction, through zero excitation and to full
excitation with current flowing in the winding in the opposite
direction. The shunt winding on one pole may also be wound with a
conductor having the same number of turns as other poles, but with
a larger size conductor, and provided with means for limiting the
current through the winding to provide the same number of ampere
turns in this coil as in other coils on other poles, and further
provided with means for bypassing the limiting means to provide
greater excitation for this pole, for returning energy to a power
supply from a load, such as for regenerative braking, without
increasing the rotational speed of a machine according to the
invention.
It should be noted that a dynamoelectric machine according to the
invention may be built with three, six or nine poles, and a
corresponding number of brushes, or in any other integral multiple
of three poles and brushes. In such an instance, poles and brushes
may be symmetrically disposed and connected in parallel. Thus, for
instance, in a nine pole machine, two sets of three field coils
each are permanently fully excited shunt fields, and the remaining
set of three coils are control coils, whose excitation may be
varied from full excitation in one polarity to full excitation in
the opposite polarity.
Thus, it is an object of the invention to provide a dynamoelectric
machine with a frame having an integral multiple of three field
poles equally spaced about the interior of the frame, each said
pole having a winding thereon, an armature rotating within said
frame, and integral multiple of two of the field poles being
excited with a fixed polarity when the dynamoelectric machine is in
operation. It is a feature of the operation that half of these
poles are north poles and half are south poles. It is an advantage
of the invention that providing the main or motor field may be done
with an exciting coil less than half the size of that required by a
device in accordance with my prior patent, resulting in a reduced
physical size and increased cooling surface for the field coils and
for the dynamoelectric machine itself.
It is a further object of the invention to produce such a
dynamoelectric machine having a control pole which may be excited
to the strength and polarity of a north pole, and to the strength
and polarity of a south pole, and all points of lesser strength in
between. It is a feature of the invention that a variable control
pole is produced by a winding through which is applied a reversible
and continuously adjustable voltage source. It is an advantage of
the invention that such a dynamoelectric machine can produce an
output voltage whose value is unaffected by residual magnetism of a
field pole and the unpredictable and unstable resulting flux.
It is a further object of the invention to provide such a
dynamoelectric machine having means for temporarily increasing the
excitation of a normally-fixed pole to produce a higher voltage on
the supply side of the machine when energy is returned from a load
on the output side of the machine, such as during dynamic or
regenerative braking. It is a feature of the invention that a
stepwise change in excitation is produced by winding the pole with
a larger wire, and interposing current limiting means to adjust its
strength, and temporarily bypassing the current limiting means to
increase the strength of the pole. It is an advantage of the
invention that where the power supply is a battery, the recharging
efficiency of the battery is increased, without substantially
increasing the shaft speed of the dynamoelectric machine.
Other objects, features and advantages of the invention will become
apparent below.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings forming a part hereof, like reference characters
indicate corresponding parts in all views.
FIG. 1 is a diagrammatic view showing a frame having three poles,
on which are field coils and stabilizing coils, and showing the
armature with the brushes spaced apart at an angular spacing of 120
mechanical degrees around the center of the armature.
FIG. 2 shows the circuit of the machine, with a power supply and a
load motor, field coils and stabilizing coils, and control of the
excitation of the control pole by a pair of potentiometers on a
common shaft, so that their brushes move together.
FIGS. 3, 4, and 5 are diagrammatic views showing the function of
the armature wiring at different stages of its operation.
FIG. 6 shows the operation of a pair of linear potentiometers
coupled to provide reversing control field excitation.
FIG. 7 shows a preferred arrangement of two potentiometers on a
common shaft, operating like the two linear potentiometers shown in
FIG. 6.
FIG. 8 shows a first excitation circuit for a pole which provides
increased excitation current only when the current through a load
motor is reversed.
FIG. 9 illustrates a circuit for regenerative braking.
FIG. 10 illustrates a polarized relay for providing increased
excitation current to a pole when the current through the load
motor is reversed.
FIG. 11 illustrates a six pole dynamoelectric machine according to
the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a three pole embodiment of a dynamoelectric machine
according to the invention having a frame 20 made of a magnetic
circuit material for providing a magnetic flux path and provided
with inwardly extending poles 22, 24, and 26, identified by poles
alpha (.alpha.), beta (.beta.) and gamma (.gamma.). Alpha and beta
poles 22 and 24 serve as motor poles in the preferred embodiment,
and gamma or control pole 26 together with beta pole 24 serve as
generator poles, under normal operation. However, a dynamoelectric
machine according to the invention proportions two electrical
powers and a mechanical power so that their signed algebraic
summation is zero. Therefore, the motor poles may act as generator
poles, and the generator poles may act as motor poles, or all poles
may act as generator poles if mechanical energy is supplied to the
machine. Poles 22, 24 and 26 are provided with windings, pole 22
carrying an alpha winding 28, pole 24 carrying a beta winding 30,
and pole 26 carrying a gamma winding 32. Alpha and beta poles 22
and 24 are shown provided with stabilization windings 34 and 36,
respectively. Rotatively disposed within frame 20 is an armature
38, carried by shaft 40, and provided with a number of armature
slots which is an integral multiple of three. In an actual
embodiment of the invention, armature 38 has forty-five slots, as
will be apparent from FIGS. 3, 4, and 5. Armature slots are
identified with numerals 1' to 45', as are commutator segments 1'
to 45' to distinguish them from other reference numerals. Armature
38 has a commutator surface 42, and three brushes, equally disposed
about commutator surface 42 at intervals of 120 mechanical degrees,
as will be apparent. For a dynamoelectric machine according to the
invention having a greater number of poles and brushes, the spacing
is 120 electrical degrees. To aid in understanding and description,
these three brushes will be defined as an A brush 44, a B brush 46
and a C brush 48.
A computer model indicates that under certain conditions such as
arrangement of field polarity, direction of rotation, saturation of
iron in the armature, the main field can be cancelled out by a
component of the armature field, causing the machine to become
unstable. Thus, to prevent a runaway, stabilizer coils should be
placed on one or two poles. The computer model indicates that
stabilization may be obtained by using the stabilization coil
arrangement given by the following matrix:
______________________________________ Brush Current to Be Used For
Excitation Poles Column 1 Column 2 Column 3
______________________________________ 22 (alpha) none -Ic Ib 24
(beta) Ic none -Ia 26 (gamma) -Ib Ia none
______________________________________
It is believed that selecting series windings to be used, and the
current and polarity to be used to excite the winding from the
matrix above is sufficient to achieve stabilization of the machine
at least in the absence of saturation and armature reaction
effects. For best results, minor adjustment in excitation may be
necessary. For this purpose, shunt resistors may be added in
parallel with stabilizer coils.
Also, based on laboratory test results, it is believed that a
useable amount of stabilization may be produced with a single
stabilizing winding applied to beta pole 24, preferably responsive
to current in C brush 48, as shown in Column 1 above.
As will be apparent, there may be numerous other arrangements of
series or parallel stabilizing coils that may be found useful in
further improving electrical and mechanical stability of a machine
according to the invention, which may be advantageously used in
connection with the invention.
Stabilization means selected from the matrix above appear in FIGS.
2, 9, and 11, FIG. 2 utilizing stabilization means from column 3,
FIG. 9 utilizing stabilization means from column 2, and FIG. 11
utilizing stabilization means selected from column 1.
Referring to FIG. 2, a circuit utilizing a dynamoelectric machine
according to the invention is shown. For clarity, the metallic
portions of poles 22, 24, and 26, and the magnetic path formed by
frame 20 have been omitted. As shown, a power supply shown as
battery 50 is connected between A brush 44 and B brush 46. Positive
terminal 52 of battery 50 is connected to a first terminal 54 of
stabilization winding 36, having a second terminal 56 connected to
A brush 44. A shunt resistor 58 is connected between positive
terminal 52 and terminal 56, to provide means for making minor
adjustments to the current flowing through stabilization winding 36
to achieve optimum stabilization. The negative terminal 60 of
battery 50 is connected to a B brush 46 through stabilization
winding 34, negative terminal 60 being connected to a first
terminal 62 of winding 34, terminal 64 of winding 34 being
connected to B brush 46. A shunt resistor 66 is connected between
first terminal 62 and second terminal 64, to provide means for
making the minor adjustment to stabilization currents flowing
through winding 34 to achieve optimum stabilization. Thus, brushes
A and B serve as motor brushes, causing the dynamoelectric machine
to rotate in direction 67, and the input voltage (E.sub.A-B), in
the absence of regeneration, is the input voltage. As will be
apparent, a dynamoelectric machine according to the invention is
direction sensitive, since reversing the rotational direction
causes both a mirror-image reversal between input and output sides,
and also causes the control sense of gamma winding 32 to be
inverted.
Power supply or battery 50 also supplies fixed excitation to alpha
winding 28 and beta winding 30, as well as variable control
excitation to gamma winding 32, through potentiometer assembly 68.
As illustrated, wire 72 is connected to positive terminal 52, and
wire 70 is connected to negative terminal 60. Wire 70 is connected
to first terminal 74 of alpha coil 28 to first terminal 80 of beta
winding 30. Wire 72 is connected to second terminal 78 of alpha
winding 28 and second terminal 76 of beta winding 30.
Potentiometer assembly 68 includes potentiometers 82 and 84, having
a common shaft 86 connected to operating mechanism 88. Operating
mechanism 88 may take the form of a control knob in a stationary
use of a dynamoelectric machine according to the invention, or may
be in the form of an accelerator pedal and linkage in a mobile
application. Potentiometers 82 and 84 have first terminals 90 and
94, respectively, connected to wire 70, and second terminals 96 and
92, respectively, connected to wire 72. As schematically shown,
potentiometers 82 and 84 have wipers 98 and 100, respectively,
connected to wires 102 and 104 respectively. Wires 102 and 104 are
connected to first and second terminals 106 and 108, respectively
of gamma winding 32. As will be apparent, rotation of shaft 86 can
move wipers 98 and 100 adjacent terminals 90 and 92, and adjacent
terminals 94 and 96, and to all points in-between, thereby
providing an excitation voltage to gamma winding 32 which may be of
a first polarity and equal in magnitude to the voltage of battery
50, or of a second opposite polarity equal in magnitude to the
voltage of battery 50, or any voltage in-between, so that control
or gamma pole 26 may act as a north magnetic pole of continuously
variable strength, and as a south magnetic pole of continuously
variable strength. Of course, a separate source of power for gamma
winding 32 may also be used, if desired.
Although the magnetic paths within a dynamoelectric machine
according to the invention are interlinked and somewhat
interdependent, it may be considered for purposes of FIG. 2 that
changing the excitation voltage applied to gamma winding 32
produces a flux in pole 26 which influences the voltage generated
in windings of armature 38 lying between A brush 44 and C brush 48.
As shown, A brush 44 and C brush 48 are connected to first and
second terminals 110 and 112, respectively, of a direct current
motor 114. As is known, a motor such as motor 114 may also act as a
generator, when power is applied to rotating shaft 116, rather than
being removed from it. As shown C brush 48 is connected directly to
terminal 112, while the connection of A brush 44 to terminal 110 is
through stabilization winding 36, as described above.
FIGS. 3, 4 and 5 illustrate the interaction between the armature
winding and the magnetic fields of a dynamoelectric machine
according to the invention. The armature and field structure is
presented in a linear manner, in a schematic form developed into a
straight line. The armature illustrated in FIGS. 3, 4, and 5 has
forty-five winding slots, although any number of slots which are
divisible by three is usable in accordance with the invention. The
armature winding is shown as a two-layer winding, each slot
containing an upper or outer conductor and a lower or inner
conductor. Of course, other winding arrangements may be used, such
as a side-by-side arrangement. Although numerous conductors are
omitted for clarity from FIGS. 3, 4, and 5, one skilled in the art
may easily fill in the remainder of the illustrated lap winding,
and modify the disclosed three-pole winding into appropriate form
for a dynamoelectric machine according to the invention having a
number of poles which are an integral multiple of three, with the
integral multiplier being greater than one.
The pitch of the armature winding is 120.degree., the armature
being wound as a lap winding. As shown in FIGS. 3, 4, and 5, for
example, a conductor section 120 is connected to commutator segment
1', and to conductor section 122, described as a separate section
for purposes of illustration only, being preferably a section of a
continuous loop, and runs along the bottom of armature slot 1 to
the armature end distal to the commutator, through knee section 124
and 126 to section 128, which runs along the upper layer of slot 16
and is connected to section 130, in turn connected to commutator
segment 2'. Commutator segment 2' is connected to a conductor
section 132, which, as is conventional for a lap winding, proceeds
through the bottom, inner or lower layer of armature slot 2' to the
upper layer of slot 17', and returns to commutator segment 3'. This
process is repeated until both lower and upper, first and second,
or inner and outer slots 1' to 45' are filled. Brushes 44, 46, and
48 are symmetrically disposed at intervals of 120 mechanical and
electrical degrees about commutator surface 42.
It should be noted that, in FIGS. 3, 4, and 5, conductor segments
which are shown as lying in the lower or inner level are
illustrated as broken lines, while conductor segments that lie in
the upper or outer portion of an armature slot are illustrated in
solid lines.
FIGS. 3, 4, and 5 differ in that the flux supplied by gamma or
control pole 26 varies from a full-strength north polarity in FIG.
3, through zero in FIG. 4, to a full-strength south polarity in
FIG. 5.
FIGS. 3, 4, and 5 show that the conductors of the illustrated lap
winding in the upper or outer layer and the conductors in the inner
or lower layer are exposed to different fields, and therefore have
different voltages induced in them as armature 38 rotates. The
voltages induced in the upper and lower layers are in series, but,
since the conductors in the lower layer are return conductors, the
voltage induced in these conductors subtracts algebraically from
the voltage induced in the conductors of the upper layer.
Brushes A, B and C identified as brushes 44, 46, and 48, divide the
armature winding into three branches. In FIG. 3, in the branch
circuit between A brush 44 and B brush 46, conductors in slots 1'
to 15' lie in the upper or outer layer, under alpha pole 22, and
conductors in slots 31' to 45' lie in the lower or inner layer,
under beta pole 24. Poles 22 and 24, in the absence of stablization
excitation, are excited with a constant voltage, and consequently
the voltage between A brush 44 and B brush 46 remains theoretically
constant during operation. As shown, conductors in slots 1' to 15'
are influenced by flux from alpha pole 22 having a south polarity,
as indicated by arrow 133, and conductors in slots 31' to 45' are
influenced by a flux having a constant north polarity, as indicated
by arrow 134. The algebraic sum of these opposing voltages, the
voltage generated by conductors under alpha pole 22 (E.sub..alpha.)
and the opposing voltage generated by conductors under pole beta
(E.sub.62 ) equals the voltage applied such as by battery 50
(E.sub.o). In short, externally, a dynamoelectric machine according
to the invention appears to act as a motor between A brush 44 and B
brush 46.
An arrow 135 illustrates the polarity of the voltage induced by the
flux of beta pole 24 in conductors in slots 31' to 45'
(E.sub..beta.) and arrow 136 identifies the opposing polarity of
the voltage induced in conductors in slots 1' to 15' by the flux
from alpha pole 22 (E.sub..alpha.).
An output voltage appears between A brush 44 and C brush 48. The
magnitude of the output voltage is related to the excitation
applied to gamma pole 26. In FIG. 3, gamma pole 26 is excited with
current sufficient to produce a flux identical in magnitude to that
of alpha pole 22 and beta pole 24, and having a north polarity, as
indicated by arrow 137. The voltage induced in conductors lying in
slots 16' to 31', lying under gamma pole 26, E.sub..gamma., is
indicated by arrow 138. The output voltage appearing between A
brush 44 and C brush 48 is the algebraic summation of the voltage
induced by conductors in slots 1' to 15' under alpha pole 22
(E.sub..alpha.) and the voltage induced in conductors in slots 16'
through 31' under gamma pole 26 (E.sub..gamma.). In the absence of
mechanical load or power input to rotating shaft 40, as shown,
induced voltage E.sub..alpha. and induced voltage E.sub..gamma. are
in series, the output voltage between A brush 44 and C brush 48 is
equal to the input voltage. E.sub.o. Thus, a dynamoelectric machine
according to the invention provides a maximum output voltage
substantially identical to the input voltage when gamma pole 26 is
excited to a full-strength north polarity.
In FIG. 4, the excitation applied to gamma pole 26 has been
adjusted to produce no net flux. It is believed that the excitation
may need to be adjusted slightly towards south excitation to
overcome the effect of residual magnetism of the magnetic material
of gamma pole 26. Thus, while the voltage between A brush 44 and B
brush 46 remains constant and equal to the applied voltage E.sub.o
such as supplied by battery 50 of FIG. 1, the voltage appearing
between A brush 44 and C brush 48 has changed. Since no flux is
produced by excitation of gamma pole 26, as indicated by the lack
of a polarity-indicating arrow head on line 137a, no voltage is
produced by conductors in slots 17' to 30', as shown by the lack of
an arrow head on line 138a, so that the algebraic summation of the
voltages appearing at A brush 44, induced primarily by alpha pole
22 and the voltage appearing at brush C is equal to one-half of
input voltage E.sub.o.
In FIG. 5, the excitation to gamma pole 26 is adjusted to produce a
flux having a strength or intensity equal to that of alpha pole 22
and beta pole 24 and having a south polarity, as indicated by arrow
137b, producing a voltage in the direction shown by arrow 138b.
Thus, as shown, the algebraic summation of the voltage appearing at
A brush 44, (E.sub.A) and the voltage appearing at C brush 48
(E.sub.C) shows that these equal and opposing voltages cancel,
yielding an output voltage of zero, since the voltage induced in
the upper layer conductors in slots 16' through 30' is cancelled by
the voltage inducted in the lower layer conductors in slots 1' to
15'.
It will be apparent from FIGS. 3, 4, and 5 that, in a similar
manner, the voltage appearing between A brush 44 and C brush 48 may
be made greater than the input voltage or less than zero, by
increasing the strength of excitation of gamma pole 26 with an
appropriate polarity. It will also be apparent that the voltage
appearing between A brush 44 and B brush 46 may be increased while
the voltage between A brush 44 and C brush 48 is held constant,
such as would be appropriate for regenerative braking, by
increasing the excitation applied to beta pole 24.
FIG. 6 shows the principal of a double potentiometer assembly 68
for reversing field excitation of gamma pole 26. Two potentiometers
82 and 84 are connected in opposition to each other, and to a
common power supply, such as power supply 50, connected to a
positive wire 72 and negative wire 70. When wipers 98 and 100 are
in the upper position shown in solid lines in FIG. 6, wiper 98 is
connected to positive voltage from wire 72, while wiper 100 is
connected to negative wire 70. When brushes 98 and 100 are in a
lower position, such as shown in broken lines in FIG. 6, wiper 98
is connected to a negative voltage, while wiper 100 is connected to
a positive voltage. In an intermediate position, wipers 98 and 100
are both connected to the same voltage, so that winding 32 receives
no excitation.
FIG. 7 shows the preferred arrangement for potentiometer assembly
68, potentiometers 82 and 84 being rotary potentiometers mounted
for rotation on a common shaft 86. The two potentiometers are
connected against each other to a power supply such as wires 70 and
72 connected to terminals 52 and 60 of power supply or battery 50.
When an operating mechanism 88, here shown as a knob, is turned,
the two wipers 98 and 100 move about their respective centers 140,
144. The voltage between wipers 98 and 100, applied to gamma
winding 32, and the resulting excitation, may be reversed in
polarity and continuously varied in magnitude in the manner shown
in FIG. 6.
Referring again to FIG. 1, during operation of motor 114, it is
possible, such as during braking of an electric vehicle driven by
motor 114, that the speed of motor 114 may become higher than that
demanded by the voltage impressed upon terminals 110 and 112, the
counter EMF from motor 114 exceeding the impressed voltage, so that
the current through the motor reverses. As a result, power is
returned to the dynamoelectric machine according to the invention.
However, the voltage appearing between A brush 44 and B brush 46
has not changed. Theoretically, this voltage will be either
substantially equal to the voltage of battery 50, or slightly less
than the voltage of battery 50, due to resistance losses in wiring
between the subject dynamoelectric machine and battery 50. To
return energy efficiently to battery 50, a voltage higher than its
output voltage should be applied to it. Therefore, the extra power
delivered to the subject dynamoelectric machine acts to increase
the rotational speed of armature 38, to dissipate the energy in
frictional and windage losses. This increased speed may be
objectionable, if the subject machine is also connected to a
mechanical load or mechanical power source, such as device 145
shown coupled to shaft 40 in FIG. 2.
To keep the speed of the subject machine constant, and increase the
voltage between A brush 44 and B brush 46 without causing higher
rotational speed of armature 38, it is believed that the excitation
of beta pole 24 may be increased. This does not affect the voltage
between C brush 48 and A brush 44, because this branch has no
conductors under beta pole 24. This extra excitation should be
supplied only when the current from the load motor 114 is
reversed.
FIG. 8 shows a suitable circuit. In FIG. 8, a booster coil 146 is
applied over winding 30 and stabilization winding 36. Therefore,
when current flows from C brush 48 to terminal 112 of motor 114,
current will flow through diode 148, bypassing booster coil 146.
However, if the current is reversed in direction, current will flow
from terminal 112 into C brush 48. In this mode, current is blocked
from flowing directly to C brush 48 by diode 148, and rather flows
into first terminal 150 of booster winding 146, out of second
terminal 152 of booster coil 146, through diode 154, to C brush 48,
thus increasing the excitation of beta pole 24. However, as will be
apparent, this may result in an increase in the size of the subject
machine to allow for this additional coil on beta pole 24.
The preferred circuit for increasing the voltage between A brush 44
and B brush 46 is shown in FIG. 9. In this circuit, the winding 154
wound on beta pole 24 is wound with the same number of turns as
winding 30, shown in FIG. 1, but with a larger conductor size,
providing a lower resistance, and a greater number of ampere-turns
for a given excitation voltage. A resistor 156 is placed in series
with winding 154 to limit the excitation of beta pole 24 to that of
alpha pole 22, in normal operation. Resistor 156 is connected in
series with winding 154, between wire 70 and first terminal 158 of
winding 154. Second terminal 160 of winding 154 is connected to
wire 72. First and second terminals 162 and 164 of resistor 156 are
joined to switch means 166 by wires 168 and 170. Wires 168 and 170
are connected to first and second terminals 172 and 174 of switch
means 166. Switch means 166 may be characterized as a relay which
is sensitive to the direction of current flow, and may be made in
numerous ways, such as by the use of steering diodes as shown in
FIG. 8 to control a low-impedance relay coil, or by the use of a
Hall-effect sensor and steering diodes controlling a high-impedance
relay, or by the use of any other means which detects the current
in wire 176 connected between C brush 48 and terminal 112 of motor
114.
In FIG. 9, the stabilization winding arrangement is chosen from
column 2 of the table above, with stabilization windings added to
alpha pole 28 and gamma pole 32. A wire 178 connected to terminal
52 of power supply shown as battery 50 is connected to a first
terminal 180 of stabilization winding 182, and also to a first
terminal 184 of stabilization winding 186. Second terminal 188 of
stabilization winding 182 is connected to A brush 44, and second
terminal 190 of stabilization winding 186 is connected to terminal
110 of motor 114. Potentiometers 192 and 194 are provided to make
initial adjustments in stabilization current to provide optimum
stabilization. Potentiometer 192 is connected between first
terminal 184 and second terminal 190 of winding 186, and
potentiometer 194 is connected between first terminal 180 and
second terminal 188 of winding 182.
FIG. 10 shows a preferred embodiment of switch means 166, in the
form of a polarized relay. Wire 176 passes through a yoke 200,
which is pivotably supported on rod 202, which in turn may be
supported in any convenient manner. Yoke 200 is suspended between a
pair of permanent magnets 204 and 206, which are provided with pole
shoes 208 and 210, respectively.
Yoke 200 is made of a magnetic material, which may be magnetized by
current flow through wire 176, the polarity of the resultant
magnetization depending on the direction of the current flow. For
forward current flow and normal operation, yoke 200 is magnetized
so as to be attracted to pole shoes 208 of magnet 204. When current
is reversed, such as during regenerative breaking of an electric
motor, yoke 200 is magnetized so as to be attracted to pole shoe
210 of magnet 206, thus actuating plunger 212 of a conventional
switch 214, having terminals 172 and 174, as shown in FIG. 9.
Support members for magnets 204 and 206 have been omitted for
clarity. Preferably, they are adhesively attached to a bracket of
non-magnetic or paramagnetic material, such as plastic or aluminum,
or clamped to such a bracket using a nonmagnetic or paramagnetic
clamping material.
FIG. 11 illustrates a six-pole embodiment of a dynamoelectric
machine according to the invention. All dynamoelectric machines
according to the invention having a number of poles which are a
multiple of three with a nonunitary multiplier have poles and
brushes connected in parallel. Therefore, the embodiment of FIG. 11
is quite similar to the embodiment of FIG. 2, but with the addition
of paralleled poles and brushes, and the use of stabilization
selected from column 1 of the table above. When feasible, the
reference numerals used in FIG. 11 will be the same as or similar
to corresponding reference numerals used in FIGS. 2 and 9 for
corresponding items. It should also be noted that the embodiment of
FIG. 11 may also incorporate beta poles 154, as shown in FIG. 9
with series resistors 156, or an additional coil and steering
diodes as shown in FIG. 8. Such modifications have been omitted
from FIG. 11 for clarity.
As illustrated, a six pole dynamoelectric machine according to the
invention has two alpha poles 28a and 28b, two beta poles 30a and
30b and two gamma poles 32a and 32b, equally spaced around armature
38a, in a serially repeating manner in the order of the Greek
characters alpha, beta and gamma. Interposed between the poles are
a pair of A brushes 44a and 44b, a pair of B brushes 46a and 46b,
and a pair of C brushes 48a and 48b. As in FIGS. 2 and 9, an A
brush is disposed between an alpha pole and a gamma pole, a B brush
is disposed between an alpha pole and a beta pole and a C brush is
disposed between each adjacent beta pole and gamma pole. The A
brushes 44a and 44b are interconnected by a jumper 220. The B
brushes 46a and 46b are interconnected by a jumper 222, and the C
brushes 48a and 48b are interconnected by a jumper 224. Armature
38a is an appropriate modification of armature 38, shown in FIGS.
3, 4, and 5, with the ends of adjacent winding loops connected to
adjacent commutator bars spaced 60 mechanical degrees from the
adjacent commutators bars where the beginnings of these adjacent
loops are connected, rather than having the start and finish of a
given loop connected to adjacent commutator bars as shown in FIGS.
3, 4 and 5.
FIG. 11 also differs from FIGS. 2 and 9 in the arrangement of
stabilizer coils, gamma poles 32a and 32b, and beta poles 30a and
30b being provided with stabilization windings. The beta poles are
provided with a stabilization windings 226a and 226b, placed in
series with the current from the pair of C brushes, and the gamma
poles are provided with stabilization windings 228a and 228b,
placed in series with the current carried by the pair of B brushes.
As shown, stabilization windings 226a has a first terminal 230
connected to terminal 112 of motor 114, and a second terminal 232
connected to a first terminal 234 of stabilization winding 226b.
Stabilization winding 226b has a second terminal 236 connected to C
brush 48b, which in turn is connected in parallel with C brush 48a
by jumper 224.
Stabilization winding 228a has a first terminal 238 connected to
wire 70, which in turn is connected to terminal 60 of power supply
50. A second terminal 240 of stabilization winding 228a is
connected to a first terminal 242 of stabilization winding 228b.
The second terminal 246 of stabilization 228b is connected to B
brush 46a, which in turn is connected in parallel with B brush 46b
by jumper 222.
As will be apparent to one skilled in the art, numerous
modifications and variations of the precise embodiments of the
invention disclosed may be made without departing from the spirit
and scope of the invention.
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